Overheating issues

[SpeicherBimmer]

So I've been doing the routine maintenance on my car and have fixed a number of little things. I changed out the coolant to the BMW type with distilled water as the old coolant was either VERY old Dexcool or extremely ancient regular stuff as it was a sewage water orangey-brown. I flushed the system and bleed it as well. Driving around it usually sits at around the 1/2 mark to about a 1/4 below half. Occasionally if I am sitting it will go maybe a hair past the 1/2 mark, but always comes down when I start moving again.Today when I got home and was idling in the garage for a min the temp gauge started creeping up and got to the 3/4 mark. I figured there was still air in the so I bled it again, but there was straight coolant coming out. I had a new T-stat to put in anyway, so I broke it apart and changed it. I found some silicate deposits in the T-stat housing and the T-stat itself looked burnt( pics attached). What could cause a T-stat to become burned looking that? Should I be worried? I'll see how she does driving to work today and post up later, but any advice would be greatly appreciated...

[jlevie]

This sounds like a failing fan clutch.

[M-technik-3]

Seal looks like it was crumbling. Antifreeze becomes acidic as it gets old so it tends to eat old stuff. As you said the coolant did not look like it had the proper mix nor type.

Might not have been distilled water either. Have you checked your fan clutch?

[SpeicherBimmer]

I thought it was the fan clutch as well but it is good...shredded up the German newspaper i can't read quite easily...

[M-technik-3]

How warm is it there still under 20c right? Did you flush the system with plain water? You might have some sludge build up in the block or even the radiator.

[SpeicherBimmer]

Yes it is still under 20c unfortunately...I flushed it with plain water till the water was pretty much clear coming from the block and radiator... I looked down in the radiator as best as I could and didn't see any sludge; the block is a different story( who knows?). I go under the car again and noticed the side of the block( passenger) seemed a bit wet under the head. I know thatthe water jacket at the back of the head is leaking, though I have no idea how to fix that without pulling the engine. There's no coolant in the oil or vice versa...

[jeffnhiscars]

Since you've addressed the fan clutch & tstat, given your description of the coolant that was in there, my vote goes with sludge. If you have access to an IF Temp Gauge check the radiator for cool spots at operating temperature. Either way I'd do a HD flush on the cooling system without the tstat (heater valve open).

I had similar symptoms & after replacing the wp, clutch & tstat more than once each over the course of a couple of years, turns out I was missing a radiator shroud

[M-technik-3]

You can reach the line one the back of the head. It's two ten mm bolts and a simple gasket. PIA but do able.

[dnguyen1963]

How old is your radiator? If you fan clutch is fine, an old radiator could be a culprit for raising temp.

[SpeicherBimmer]

O-k, here's an update. It is relatively warm here today at 74 F. Took the car out for a spin to Bitburg on the autobahn, up until the A-60 she was sitting half-way between the 1/4 and 1/2 mark on the gauge; all is well. I get on the A60 and am cruising at around 130kmh and the gauge starts rising slowly till it gets to just pass the 1/2 and stays there for about a min...I didn't slow down or anything and just watched it. By the time I got to the Bitburg exit and had coasted won in gear the gauge had dropped back down to the 1/4 mark and didn't even touch the 1/2 mark the rest of the trip. Water pump maybe as it started getting hot at highway speeds? I tried finding an IR thermo., but nobody around here seems to carry them...

[Mr. Burns]

This almost sounds symptomatic to the notorious "dancing gauge" issues most e30's get with age.

Does you gas gauge go from 1/4 to half and back? Same electrical issue persists itself on the temp gauge.

Oftentimes my temp needle will creep to just a little over halfway, and I give a good whack above the gauge cluster on the dash and it drops immediately down to just under the 1/2 way mark.

If you truly are overheating, a tell tale sign would be to check you spark plugs... If they are "white" that would indicate overheating...

Good luck!

[jlevie]

The road trip experience could be something as innocuous as a gauge issue, but it could be something more serious like a leaking head gasket that is allowing air to be pumped into the cooling system. An inexplicable loss of coolant or getting air from a fully bled cooling system are evidence of a head/gasket problem.